# We invent a machine that lets amateurs build machine guns. What happens? **URL:** \ **Category:** Great Debates\ **Created:** [June 7, 2010, 12:06am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210 "2010-06-07T00:06:06Z")\ **Posts on this page:** 13\ **Page:** 4
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [June 7, 2010, 6:40pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/61 "2010-06-07T18:40:46Z")
> [@Oakminster](#): > > I’m not the one that’s angry or calling people irrational. Sorry, you seemed angry when you claimed I must be afraid of guns. I also took your complete inability to stay on topic and simply demand time after time that everyone should have a machine gun if they want one as someone who wasn’t rational about the topic. > [@](#): > > And, since you’re back, please respond to me earlier question about what, exactly, you think can be done with a fully automatic AK 47, but cannot be done with a semi automatic version of the same rifle? Putting a lot of lead downrange seems like an obvious advantage. I tell you what, go to the Pentagon and tell them they’re stupid for having automatic weapons. ---
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [June 7, 2010, 6:48pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/62 "2010-06-07T18:48:21Z")
> [@Todderbob](#): > > Actually, the current steel and titanium isn’t strong enough to make a sword, much less make a container than can hold the kind of explosions that go on in gun barrels, and it’s unlikely that our current technology will progress into one that could reasonably soon. True, for some values of unlikely. 😃 > [@](#): > > On the other hand, polymers are easy to work with and fabricate (layer by layer) and can be strong enough and have high enough melting points (theoretically, at least) to be used as selective fire rifle chambers. And since polymers lend themselves to be fabricated much more quickly and easily than metals, it’s easier to presume the development of a new polymer that that uses current fabrication technologies than it is new fabrication technologies. As I posted above, they are currently working with ceramics, and good on them. But as I also mentioned the hot isostatic pressing (which increases the size of the home unit some) makes the metals a lot stronger than sintering alone. I certainly won’t be surprised if we have amazing metal quality a decade or two down the line. > [@](#): > > Also, your response has shown that you’re not interested in furthering the debate, you’re interested in being right. I put forth a (semi)plausible way that both parties could agree to the premise of the OP and have a discussion about it, without either side conceding ground on whether or not the fabricator would have to be magical, and instead of using it and moving on with the discussion at hand you’ve shot it down as if it were nonsensical. Not at all, I’m all about the debate. I’m just saying that the polymer is unnecessary to the situation. I’d in fact like there to be awesome polymers. ---
**Author:** ![Todderbob](https://avatars.discourse-cdn.com/v4/letter/t/e47774/32.png) [@Todderbob](https://boards.straightdope.com/u/Todderbob)\ **Post date:** [June 7, 2010, 7:15pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/63 "2010-06-07T19:15:08Z")
> [@Lobohan](#): > > Putting a lot of lead downrange seems like an obvious advantage. I tell you what, go to the Pentagon and tell them they’re stupid for having automatic weapons. You missed the bit where military personnel are trained not to use the burst/full auto options except under specific circumstances? (Like when they’re defending a well stocked and fortified base being overrun.) ---
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [June 7, 2010, 7:17pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/64 "2010-06-07T19:17:41Z")
> [@Todderbob](#): > > You missed the bit where military personnel are trained not to use the burst/full auto options except under specific circumstances? (Like when they’re defending a well stocked and fortified base being overrun.) Did you stop to think about how those specific circumstances apply to criminals? Why do criminals use fully automatic guns in drive by shootings? (I know there aren’t really that many drive by shootings by the way). ---
**Author:** ![Todderbob](https://avatars.discourse-cdn.com/v4/letter/t/e47774/32.png) [@Todderbob](https://boards.straightdope.com/u/Todderbob)\ **Post date:** [June 7, 2010, 8:03pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/65 "2010-06-07T20:03:40Z")
> [@Lobohan](#): > > Did you stop to think about how those specific circumstances apply to criminals? Yes. A criminal is in his well fortified base of operations, with hundreds of thousands of rounds of ammo and a supply chain that’s well organized enough to get him and his cohorts who are mounting an overlapping defensive screen sufficient ammunition to reload and resupply. Oh wait… > [@Lobohan](#): > > Why do criminals use fully automatic guns in drive by shootings? (I know there aren’t really that many drive by shootings by the way). First, lets see a cite saying most criminals use fully automatic guns in drive by shootings. I don’t think they do. My contention is it is more likely that most use semiautos and spray and pray. But even accepting your Hollywood version of reality, for intimidation factor, not efficacy. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [June 7, 2010, 8:05pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/66 "2010-06-07T20:05:12Z")
> [@Lobohan](#): > > Why do criminals use fully automatic guns in drive by shootings? (I know there aren’t really that many drive by shootings by the way). Do criminals really typically use fully automatic guns in drive-by shootings? Yes, the military uses fully automatic weapons. But infantrymen almost never carry submachine guns, they carry rifles, and are trained to use single fire almost all the time. Why is this? Because spraying a full magazine of rounds downrange is usually less effective than firing one aimed round. Yes, troops also use machine guns. But these are used as support weapons. If machine guns were so effective, then why aren’t all troops equipped with machine guns? ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [June 8, 2010, 2:07am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/67 "2010-06-08T02:07:14Z")
> [@Lobohan](#): > > They can do tool steel and titanium now. The can do alloys now. It isn’t Star Trek technology. It would just require a bit more than we can do now. I don’t actually know that we couldn’t do it today, can we get a materials scientist in the house? I wasn’t the materials guy, but I worked 5 years for a leader in the field. Yup, Ti and tool steel were our best stuff. Surface finish was poor. Worse than a mediocre casting, much worse than a good casting…maybe not as bad as a really poor casting. Warpage and internal stresses are huge…but by all means buy a couple of the machines and see for yourself. (I own a small amount of stock) ---
**Author:** ![SteveG1](https://avatars.discourse-cdn.com/v4/letter/s/bb73d2/32.png) [@SteveG1](https://boards.straightdope.com/u/SteveG1)\ **Post date:** [June 8, 2010, 2:14am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/68 "2010-06-08T02:14:52Z")
> [@Oakminster](#): > > A few enthusiasts make one, and discover the damn thing can go through a mortgage payment’s worth of ammo in a very short time. Then it gathers rust in the garage. This. Ammo gets expensive, pretty fast in full auto 😃 ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [June 8, 2010, 11:35am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/69 "2010-06-08T11:35:07Z")
> [@Lobohan](#): > > [The military is looking to sintered ceramic gun barrels.](http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBIQFjAA&url=http%3A%2F%2Fwww.dtic.mil%2Fcgi-bin%2FGetTRDoc%3FLocation%3DU2%26doc%3DGetTRDoc.pdf%26AD%3DADA430400&ei=yjkNTOGMKaLcM9i8ga8L&usg=AFQjCNFyWriyLJIUftcLkLVf-FfslEWvOQ&sig2=0g4nidMPIdW_TP6JI0rQXg) That cite shows no such thing - it’s a materials evaluation of conventionally-produced ceramics. No rapid fabrication techniques were evaluated at all. To whit: > [@](#): > > \*\*Traditional \*\*sintering methods were used to fabricate all materials, with the exception of > the SiAlON (STK4), which was subjected to a post sintering hot isostatic pressing > process. > [@](#): > > And coupled with _hot isostatic pressing_ it is currently producing quality metals. [http://www.tms.org/pubs/journals/jom/9812/das-9812.html](http://www.tms.org/pubs/journals/jom/9812/das-9812.html) Are you alleging that HIP is a process that could scale to the desktop, and the amateur home user? Really? With thousands of degrees and thousands of atmospheres of pressure? ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [June 8, 2010, 11:46am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/70 "2010-06-08T11:46:23Z")
:smack:I guess you are, at that: > [@Lobohan](#): > > But as I also mentioned the hot isostatic pressing (which increases the size of the home unit some) ---
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [June 8, 2010, 4:41pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/71 "2010-06-08T16:41:51Z")
> [@MrDibble](#): > > :smack:I guess you are, at that: I was. I was imagining a futuristic method that didn’t require as high pressures or heat. Although they do currently have something the size of a cabinet that can do HIP on a small scale, at current pressures and heat requirements. ---
**Author:** ![Drew\_Kit](https://avatars.discourse-cdn.com/v4/letter/d/7cd45c/32.png) [@Drew\_Kit](https://boards.straightdope.com/u/Drew_Kit)\ **Post date:** [June 18, 2010, 11:40am UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/72 "2010-06-18T11:40:51Z")
> [@TriPolar](#): > > burning up ammo doesn’t mean much, you can just print some more. 3D printing wouldn’t be able to print live bullets, just empty shells. ---
**Author:** ![Zeriel](https://avatars.discourse-cdn.com/v4/letter/z/58956e/32.png) [@Zeriel](https://boards.straightdope.com/u/Zeriel)\ **Post date:** [June 18, 2010, 3:43pm UTC](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210/73 "2010-06-18T15:43:40Z")
> [@Lobohan](#): > > They can do tool steel and titanium now. The can do alloys now. It isn’t Star Trek technology. It would just require a bit more than we can do now. I don’t actually know that we couldn’t do it today, can we get a materials scientist in the house? My uncle does this kind of fabrication work, actually (among others–he’s a prototype machinist, and his foundry essentially produces exactly what we’re talking about here–high-precision prototyped parts with various processes). I’m going to lay it out for you as briefly as I can. Sintering (the process you’re discussing, with powdered metals being laser fused) inherently and unavoidably produces parts that are weaker both in the aggregate and in different ways than casting molten metal. Blake’s objection is essentially that a machine that can sinter with sufficient accuracy to produce materials of the same strength and weight as firearm components can also produce things that are valuable enough and precise enough such that there will be a net reduction in criminal motive. Incidentally, any process that can do this with metal to any degree of precision could be easily adapted to produce circuit boards, IMHO–ceramics can be sintered, and you’d just need to pause the process a few times to alternate sintering a ceramic dielectric layer and a copper one. I’m not 100% sure a suitable ceramic for this exists yet, but meh, we’re talking about the future. =) I’m not sure if it could produce actual ICs, granted. Similarly, the objections of others are also pretty reasonable–you can’t fabricate bullets with this, and hand-loading them (after using this process to make the casings) is non-trivial. Ultimately, I don’t think much would change. We’d continue to make possession of such weapons illegal. Perhaps a few more people would acquire them, but they’re not as easy to kill people en masse with as you think, and people who want to kill en masse already have explosives with much greater ability to do that available to them. They aren’t particularly any more effective for the criminal element, IMHO–if they were, we’d see more use of them on our streets today. [Previous page](https://boards.straightdope.com/t/we-invent-a-machine-that-lets-amateurs-build-machine-guns-what-happens/542210.md?page=3)